Before I ever set foot in Katharine and James' south London home, I knew that it would be beautifully designed to the last detail. After 13 years spent working for UK design bible The World of Interiors, Katharine certainly knows what she likes: a stylish mix of classic British and French country style, with lots of pattern, sparkle and shine.

James, too, works in the London design industry, having managed sales at several of the city's top furniture makers and upholsterers for years. This was a big help when it came to sourcing and re-upholstering much of the couple's furniture; many of the pieces Katharine gravitates toward are antique or traditionally-styled, but the fabrics she loves are modern. The result is a quirky mix of elegant and fun pieces.

Since buying the four-level house two years ago, Katharine and James have left nothing untouched, completely re-painting their home in Farrow & Ball colors and lovingly filling it with the pieces that mean the most to them. But it wasn't only cosmetic work these two undertook; they also completely gutted the kitchen and both bathrooms, turning them from "frightfully dated" to classic and chic.

Despite the serious work already done to their home, Katharine and James have even more in mind for the future. An eventual kitchen extension is planned for downstairs, as is the creation of a new bedroom next door for a future au pair. The top floor attic room, currently unfinished, will make a charming bedroom for daughter Amelie once she outgrows the nursery.

After Amelie's birth last year, Katharine decided not to return to the publishing rat race and instead put her enviable design and sourcing skills (and serious contacts within the design industry) to use for others. She's just launched Katharine Howard Style, a sourcing, styling and design service for busy London clients. The business covers all her passions: fashion, lifestyle goods, and of course, interiors.

"A lot of my work is just personal shopping for busy people, but there's another element" Katharine tells me. "Sometimes clients just need a cheerleader, someone to hold their hand and reassure them that they do have great taste, that everything will look fab. That's where I come in." With design confidence like Katharine's, I have no doubt.

Inspiration: I have been inspired by so many fabulous hotels, restaurants, and the gorgeous shoots in my favorite magazines, as well as interior boutiques in London, NY, Paris, Milan, and LA. Another huge source of inspiration for me is visiting flea markets in France, which is a prerequisite for all summer holidays!

Favorite Element: I love the feeling of space in our bedroom and sitting room. We feel so lucky to be on four floors — it's great for parties!

What Friends Say: I think they like it!

Proudest DIY: I have to confess not to have done too much DIY, but James has plenty of proud stories to tell, I'm sure… and I did paint the kitchen floor.

Biggest Indulgence: The fabrics have to be my biggest indulgence. I just can't resist gorgeous linens and hand-blocked prints. They're an investment that really creates the distinctive look we love, and make every piece of furniture that bit more beautiful!

Best Advice: If you're renovating, it would be to use good builders who are as perfectionist as you are!

Dream Sources: Honestly, the same sort of places where I've actually purchased items: high-end fabric houses, French flea markets, the London shops I love. Interior design is my big indulgence; I love being at home, so I try to make it as beautiful as possible!